Apparatus for fire-foam production



Nnv. 11, 1930.

P. w. PRUTZMAN 1,781,300 APPARATUS FOR'FIRE FOAM PRODUCTION Filed Sept.28, 1927 IN ENTOP Patented Nov. 11, 1930 PAUL W. PBUTZMAN, h L08 GELES,CALIFORNIA APPARATUS FOR FIBIELZE OAM PRODUCTION Application filedSeptember 28, 1927. Serial No. 222,589.

i The art .ofextinguishing fires in general, and particularly oil fires,by means of Foamg 1 its? or Firefoam is'very well known and qunderstood.It consists in bringing into ado mixture solutions of aluminum sulfate,hy-

drogen, sodium-carbonate (baking soda or I more briefly soda), and astabilizer or sub stance having the property or" increasing the surfacetension of aqueous liquids, such for instance as glue or licorice. It iscustomary to make one solution, lmown as the (a) or acid solution, ofthe aluminum sulfatealone, and another, known as the (b) or sodasolution, of a mixture of soda and stabilizer and 5 to make these twosolutions of-such strengths vthat their usein equal proportions willproduce the largest yield of foam without wast- ;age of chemicals. p 7.By the admixture of said ingredients in solutions of thepropervstrength a very dense and tenacious foam is formed which, as itconsists mainly of water and is sufiiciently, light to float on oil, isa highly efiicacious and valuable agent for extinguishing fires.

It has heretofore been the custom either to prepare the solutions inadvance and distribute them by means of duplicate pipe lines to suchparts ofa plant as require protection, or to store small quantities ofthe solutions in ressure tanks mounted on wheels, which can he taken tothe seat of the fire. The first system isdisadvantageous in that therequired investment is very heavy, and more particularly in thatthecontents of the solution tanks is necessarily limited and the time reuired .for recharging them quite extended. t has often occurred thatthese tanks have become exhausted in the course of a stubborn fire, andthat before they could be refilled the fire had gotten quite out ofhand.

x The second system is disadvantageous in,

that the output in actual foam of the largest unit which canbe takenfrom one point to another is so trifling that these portable tank unitscan handle only the smallest fires.

An object of my invention is to provide a cheap and efi'ective means forthe continu ous production of solutions of the foam chem;

icals from their dry salts, thus doing away m with the requirement forany storage of solution and avoiding a possible failure of solutionduring the course of a fire. In this view of my invention the apparatusis adapted to be used in connection with an existing system of duplicatedistributing lines for solution. a

A further object of my invention is to provide a simple and efi'ectiveportable apparatus which can be taken to a point adjacent to the seat ofthe fire and there, being sup lied to solely with water and the twochemica s in bulk, will supply for an indefinite period streams ofseparate solutions of the two chem icals, which can be separatelyconducted to the actual fire and there intermixed in any B5 preferredform of mixing head.

Further objects and advantages of my invention will be evident from aninspection of the accompanying drawing in which- Fig. 1 is a view partlyin elevation and partly in cross section, illustrating a comleteembodiment of my invention in a preerred form. F ig. 2 is a diagrammaticview of an orifice plate showing parts thereof broken away.

Referring to the drawing, numerals 1 and 2 indicate conical bottomedsteel tanks for preparing respectively the a and b solutions. 3 is aninlet pipe for water from any convenient source of supply, and 4--4 aregauge marks for indicating a constant height to which the tanks are tobe kept filled.

Pipe 3 branches into two pipes 5 and 5, controlled by the valves 6 and 6and the meters 31 and 31 shown in such lines are 35 also convenient fordetermining the rate of flow of water, but are not essential. Thesepipes enter tanks 1' and 2 at substantially their bottoms, as indicatedat 7--7, and beneath the umbrellas or inverted funnels 8--8. The upperends of these funnels are made fast to the suction pipes 9"-9" but donot communicate therewith. The lower edges of the funnels are so formedas to closely approach the tank cones 10-10, leaving the annularopenings 11-11 each of which should have approx mately the area of aninlet pipe 5.

The pump suction pipes 9"9 are made fast in the oints of the cones andrise to a height of a at six inches below the liquid level marks 4-4.These pipes communicate with the suctions of the rotary or othersuitable pumps 12 and 12"., driven at equal speed as by the pulley 13from a commonsource of power not shown. If the unit is to be port-= ablethis source of power-is preferably a de-' pendable high-speed throttlinggasoline en-- gine, such for instance as the engine driving the truck onwhich the unit is mounted.

The pumps 12 discharge into lines l f --14 by which the solutions pumpedout of tanks 1 and 2 are conveyed through the lines IS -15 (which may beof pipe, hose or both) to the mixing head.16 by WlllCh the solutions areintermixed, converted into foam and directed onto the fire.

Between the lines 1 1 and 15 are interposed a control valve 17 and ameter 18, the same fittings being correspondingly placed in the (2lines. A bypass line 19 connects the dischar e line 14 with the waterinlet 5, and in this bypass is placed the release valve 20 so connectedas to carry any excess discharge of pump 12 back into tank .1. Thisbypass enables the pump to be run at constant speed rod 2424 and slidingin a cylinder 25-25. 4-4

The assembly of pistons and rod is recipro: cated by a single crank (orother suitable mechanism) 26 driven by a band wheel 27 at some suitablespeed which is pro ortioned to the speed of the engines driving t epumps.

In operation, these pistons, at the left end of their stroke, registerthe chambers 28-28 with corresponding openings 29 29 in the bottoms ofhoppers 30 -30". At the right end of the stroke the openings 29 areclosed and the powders contained in the chambers 28 are dumped into thecorresponding chutes 3O-30 by which they are carried into tanks 1 and 2respectively. It is considered advantageousto allow these powders tofree themselves from air in the chutes 30 before passing into the bodiesof liquid contained in the tanks, but they may if preferred be dumpeddirectly into the tanks and the chutes omitted. The relative quantitiesof powder carried by each chamber 28 maybe varied by varying its length(without altering the piston stroke) or by wrapping a bulky material(such as rope or flax packing) around the rod.

It will be understood that this particular method of feeding thechemicals is not an essential part of my invention, and that othermeans, such as screw conveyors or small bucket, elevators may be used,provided they give a dependably constant feed-of each powder.

In the operation of my device the-following steps are taken. 'Waterbeing connected to pipe 3, the valves 6 and 6 are opened until themeters 31 and 31 indicate the predetermined rate of fiow,'that is, therate at which solutions will later be pumped from the tanks.

If-"the apparatus is to be used in a situation where the Water pressureis reasonably constant, time in starting will be saved by providingstopcocks with dials and pointers, located as at 32 32 which can be leftin adjustment, the valves 6--6' being .then used as stop valves only.

At the time the water flow is started the feed of dry chemicals isstarted, these passrate of flow of solution through the pipes 159-15" tothe mixing head 16. The final step is to readjust the water supplybymeans of the stopcocks 32 until the liquid stands level in tanks 1 and 2at the gauge marks These balancing up steps having been completed, theapparatus will continue to deliver, indefinitely, equal streams ofsolutions of correct strength, provided only that the hoppers be keptfilled with their appropriate chemicals. At the termination of a run thetanks may be pumped empty by closing the water valves 6-6 and openingthe drain valves 33-33 the feed of chemicals having meanwhile beenstopped.

While the apparatus illustrated in the drawing has the appearance of alar e and permanent set, and while it may rea ily be constructed in suchsize, I would have it understood that it may also be constructed of suchdimensions as to make it readily portable. For illustration, a unitproducing 100 allon's per minute of each solution, equivaent, whenproperly mixed, to 2000 gallons per minute of foam (the rate ofexpansion eing about ten to one), is suflicient to-handle a very largefire. Such unit would require two pumps havinga full speed capacity ofsay 125 gallons ppr about 150 pounds eac Tanks 1 and 2 should not haveless than 1 minute capacity and preferably should holda supply for 2minutes, or 200'gallons each. The dimensions of such tanks would beabout 3' diameminute, weighing matically illustrated in Fig. 2, in

ter, 3' cone.

The reagents weigh about 1 pound per 23 cubic inches, and as gallons ofa solution require 60 pounds and of 1) solution 40 pounds of reagent, aplunger 4 diameter making 20 strokes per minute would re quire an achamber 6 long and a b chamber 4" long.

The water inlet main 3 should be say 3" diameter, branching to two 2pipes, and the solution outlets should be 2 pipe size. The entireapparatus, including pumps,

4" height on side and 2' height of weigh, readily small truck for trans-As replacingthe control of the volumes of solutions and of water bymeans of valves and meters as shown, it is permissible, and is often adesirable modification of my invention, to pass these solutions throughorifice plates (as indicated at 18 and 18 in Fig. 1) calibrated todeliver the required or preferred quantities of liquid at a certaindefinite rate of rotation of the prime mover, and to maintain thesolution level in the tanks by means of an ordinary float valve. The useof such plates and valves will do away with the necessity of any handregulation whatever except control of the speed of h the driving engine.

The orifice plates 18 and 18 are diagramwhich 3434 are pipe flanges, 35is a hard metal plate having an opening or orifice 37 of predeterminedarea, and 36--36 are bolts for retaining the plate between the flanges.This water into said tanks in predetermined proportion; pumping meansfor separately and continuously withdrawing said solutions from saidtanks and for separately forcing said solutions to a point ofintermixture thereof, and means or proportioning the quantities of saidsolutions delivered by said pumping means, each said proportlonlng meanscomprising a bypass communicating between the discharge side and thesuction comprising:

side of said pumping means, a release valve in said bypass formaintaining a predetermined pressure on said discharge side, and anorifice in said discharge between said pump and said point ofintermixture for discharging a predetermined flow of liquid at saidpredetermined pressure.

2. An apparatus for continuously and simultaneously roducing dissimilarsolutions of foam pro ucing chemicals, comprising: tanks for maintainingseparate bodies of solution of said chemicals; means for separatelyfeeding said chemicals in the form of dry powders into said tanks; meansfor agitatmg the contents of said tanks to facilitate solution of saidpowders; means for admitting water into said tanks to maintain apredetermined liquid level therein; pumping means for separately andcontinuously drawing streams of said solutions from said tanks and forseparately forcing said streams to a point of intermixture thereof, andmeans or proportioning said streams, each said prosi e, and an orificein said pump and said point of intermixture for discharging apredetermined fioW of liquid at said predetermined pressure.

In witness that I claim the foregoing I ave hereunto subscribed my namethis 20th day of September,1927.

PAUL W. PRUTZMAN.

with

